Question

A $95 graphing calculator is on sale for $85.50. The percent decrease is

Answer 1

Well, it went down from 95 to 85.5, so it dropped by $9.5.

if we take 95 to be the 100%, what is 9.5 off of it in percentage?

$\bf \begin{array}{ccll} amount&\%\\ \text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\ 95&100\\ 9.5&p \end{array}\implies \cfrac{95}{9.5}=\cfrac{100}{p}\implies p=\cfrac{9.5\cdot 100}{95}$